The present invention relates to a portable oil suction device for sucking the engine oil out of an engine.
U.S. Pat. No. 5,002,154 discloses a portable oil suction device for use to draw the engine oil away from an engine. This device mainly comprises a top cover 81, an oil tank 82, a bottom cover 83, a pump to cylinder 84, a plunger 85, a fuse valve 86, and an exhaust hole 87. This structure of portable oil suction device is still not satisfactory in function. When the engine oil is drawn into the oil tank, bubbles will be produced. Furthermore, an oil leakage tends to occur at the connecting area between the oil tank 82 and the bottom cover 83.
FIG. 2 strops another structure of portable oil suction device in which an annular air bag 97 is mounted around the pump cylinder for eliminating the formation of bubbles during the operation of the portable oil suction device, a float mechanism 96 is installed in the bottom side of the top cover to automatically stop the air passage when the oil level inside the oil tank reaches the predetermined range, and hand-operated relief valve 99 is installed to release air out of the oil tank. However, this structure of portable oil suction device still has drawbacks. As indicated in FIG. 2, the top cover 92 has a tubular top flange 922 with two symmetrical protruding portions 923 and recessed portions 924, the plunger rod 91 has two opposite retainer rods 912 near the cross hand-hold portion 911. When the plunger rod 91 is moved to the lowest position, the retainer rods 912 are respectively fitted into the recessed portions 924, and therefore the the portable oil suction device can be conveniently carried by hand through the cross hand-hold portion 911. However, when the portable oil suction device is filled up with the engine oil and carried by hand, the protruding portions 923 of the tubular top flange 922 tend to break. Another drawback of this structure of portable oil suction device is that the oil sealing ring 943, which seals the gas between the bottom cover 95 and the oil tank 95 tends to be damaged, causing an oil leakage. Furthermore, the floating control valve 96 is expensive to manufacture and complicated to install because the float 963 of the floating control valve 96 is mounted on two separate metal plates 998 and 999.